Scientific Journal Impact Factor (SJIF): 1.711 International Journal of Modern Trends in Engineering and Research www.ijmter.com @IJMTER-2015, All rights Reserved 622 e-ISSN: 2349-9745 p-ISSN: 2393-8161 Comparative Analysis of BER Performance under QAM-OFDM System Over AWGN and Rayleigh Fading Channel Chandrakant Tiwari 1 , Mr. Abhishek Garg 2 M.Tech Student 1 , Associate Professor 2 1,2 Department of Electronics and Communication Sushila Devi Bansal College Of Technology Indore (M.P.), India Abstract - The fast development of modern communication techniques, the demand for reliable high data rate transmission is increased signification, which stimulate much interest in modulation technique. The QAM is one of the adaptive modulation techniques that are commonly used for wireless communications. Different order modulations allow sending more bit per symbol and thus achieving higher throughput or better SNR are needed to overcome any interference and maintain a certain BER. This paper at developing a simulink model to simulate different types of QAM modulation and demodulation techniques at different bit rates. Orthogonal Frequency Division Multiplexing (OFDM) was originally developed from the multi-carrier modulation techniques used in high frequency military radios. Also we are used Orthogonal Frequency Division Multiplexing (OFDM) technique with AWGN channel and Rayleigh channel. Result presented in this paper the BER tool under Matlab R2013a is used to evaluate the performance of modulation technique through draw the BER versus SNR (Eb/N0). Keyword - QAM, OFDM, AWGN, BER, SNR I. INTRODUCTION WiMAX is the system for wireless broadband access. It is based on IEEE 802.16 standards which are mainly based on Orthogonal Frequency Division Multiplexing (OFDM) technology[1]. OFDM is a wideband modulation scheme using multicarrier digital communication. The fixed and mobile versions of WiMAX have slightly different implementations of the OFDM physical layer. Fixed WiMAX, which is based on IEEE 802.16-2004, uses a 256 FFT-based OFDM physical layer. Mobile WiMAX, which is based on the IEEE 802.16e-20055 standard, uses a scalable OFDMA-based physical layer. In the case of mobile WiMAX, the FFT sizes can vary from 128 bits to 2,048 bits. Table below shows the OFDM- related parameters for both the OFDM-PHY and the OFDMA PHY. The parameters are shown here for only a limited set of profiles that are likely to be deployed and do not constitute an exhaustive set of possible values. The demand for high-speed mobile wireless communications and use of the radio spectrum is rapidly growing with terrestrial mobile communication systems being just one of many applications vying for suitable bandwidth. These applications require the system to operate reliably in non-line-of-sight environments with a propagation distance of 0.5 - 30 km, and at velocities up to 100 km/hr or higher. This operating environment limits the maximum RF frequency to 5 GHz, as operating above this frequency results in excessive channel path loss, and excessive Doppler spread at high velocity[1].
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Scientific Journal Impact Factor (SJIF): 1.711
International Journal of Modern Trends in Engineering
and Research www.ijmter.com
@IJMTER-2015, All rights Reserved 622
e-ISSN: 2349-9745
p-ISSN: 2393-8161
Comparative Analysis of BER Performance under QAM-OFDM System
Over AWGN and Rayleigh Fading Channel Chandrakant Tiwari1, Mr. Abhishek Garg2
M.Tech Student1, Associate Professor2 1,2Department of Electronics and Communication
Sushila Devi Bansal College Of Technology Indore (M.P.), India
Abstract - The fast development of modern communication techniques, the demand for reliable high
data rate transmission is increased signification, which stimulate much interest in modulation technique.
The QAM is one of the adaptive modulation techniques that are commonly used for wireless
communications. Different order modulations allow sending more bit per symbol and thus achieving
higher throughput or better SNR are needed to overcome any interference and maintain a certain BER.
This paper at developing a simulink model to simulate different types of QAM modulation and
demodulation techniques at different bit rates. Orthogonal Frequency Division Multiplexing (OFDM)
was originally developed from the multi-carrier modulation techniques used in high frequency military
radios. Also we are used Orthogonal Frequency Division Multiplexing (OFDM) technique with AWGN
channel and Rayleigh channel. Result presented in this paper the BER tool under Matlab R2013a is used
to evaluate the performance of modulation technique through draw the BER versus SNR (Eb/N0).
Keyword - QAM, OFDM, AWGN, BER, SNR
I. INTRODUCTION
WiMAX is the system for wireless broadband access. It is based on IEEE 802.16 standards which are
mainly based on Orthogonal Frequency Division Multiplexing (OFDM) technology[1]. OFDM is a
wideband modulation scheme using multicarrier digital communication. The fixed and mobile versions
of WiMAX have slightly different implementations of the OFDM physical layer. Fixed WiMAX, which
is based on IEEE 802.16-2004, uses a 256 FFT-based OFDM physical layer. Mobile WiMAX, which is
based on the IEEE 802.16e-20055 standard, uses a scalable OFDMA-based physical layer. In the case of
mobile WiMAX, the FFT sizes can vary from 128 bits to 2,048 bits. Table below shows the OFDM-
related parameters for both the OFDM-PHY and the OFDMA PHY. The parameters are shown here for
only a limited set of profiles that are likely to be deployed and do not constitute an exhaustive set of
possible values. The demand for high-speed mobile wireless communications and use of the radio
spectrum is rapidly growing with terrestrial mobile communication systems being just one of many
applications vying for suitable bandwidth. These applications require the system to operate reliably in
non-line-of-sight environments with a propagation distance of 0.5 - 30 km, and at velocities up to 100
km/hr or higher. This operating environment limits the maximum RF frequency to 5 GHz, as operating
above this frequency results in excessive channel path loss, and excessive Doppler spread at high
velocity[1].
International Journal of Modern Trends in Engineering and Research (IJMTER)